LMP-1 down-regulates BLIMP1α expression in primary GC B cells and transformed B cells. (A) Ectopic expression of LMP-1 in GC B cells was confirmed by Western blotting or was published before.³¹  (B) Quantitative RT-PCR analysis of BLIMP1α mRNA in CD10⁺ GC B cells from 5 separate donors after transfection with LMP-1 (pSG5-LMP-1 or pcDNA3.1-LMP-1) or vector control only (pSG5 or pcDNA3.1); LMP-1 down-regulated BLIMP1α mRNA in all samples. (C) LMP-1 also down-regulated BLIMP1α mRNA in both CD77⁻ (centrocytes [CCs]) and CD77⁺ (centroblasts [CBs]) subsets of CD10⁺ cells. (D) Immunohistochemistry revealed that the expression of BLIMP1α (gray) and LMP-1 (red) were mutually exclusive in B95.8 cells. Magnification ×800. Images acquired with 60×/1.40 NA oil immersion objective lens (Nikon Ltd).